Analyte sensor and apparatus for insertion of the sensor

ABSTRACT

An apparatus for insertion of a medical device in the skin of a subject is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 17/009,647, filed Sep. 1, 2020, which is a continuation of U.S.patent application Ser. No. 16/736,728, filed Jan. 7, 2020, now U.S.Pat. No. 10,786,190, which is a continuation of U.S. patent applicationSer. No. 15/994,129, filed May 31, 2018, now abandoned, which is acontinuation of U.S. patent application Ser. No. 15/475,647, filed Mar.31, 2017, now U.S. Pat. No. 9,993,188, which is a continuation of U.S.patent application Ser. No. 15/192,531, filed Jun. 24, 2016, now U.S.Pat. No. 9,636,068, which is a continuation of U.S. patent applicationSer. No. 12/698,129, filed Feb. 1, 2010, now U.S. Pat. No. 9,402,544,which claims priority to U.S. Provisional Application No. 61/149,639,filed Feb. 3, 2009, all of which are incorporated herein by reference intheir entireties for all purposes. This application is further relatedto U.S. patent application Ser. No. 12/698,124, filed Feb. 1, 2010, thedisclosure of which is incorporated by reference in its entirety hereinfor all purposes.

FIELD OF THE INVENTION

The present invention relates generally to an inserter device, forexample, to insert an analyte sensor and/or an infusion set in an animalsuch as a human.

BACKGROUND OF THE INVENTION

Diabetes Mellitus is an incurable chronic disease in which the body doesnot produce or properly utilize insulin. Insulin is a hormone producedby the pancreas that regulates blood sugar (glucose). In particular,when blood sugar levels rise, e.g., after a meal, insulin lowers theblood sugar levels by facilitating blood glucose to move from the bloodinto the body cells. Thus, when the pancreas does not produce sufficientinsulin (a condition known as Type 1 Diabetes) or does not properlyutilize insulin (a condition known as Type II Diabetes), the bloodglucose remains in the blood resulting in hyperglycemia or abnormallyhigh blood sugar levels.

The vast and uncontrolled fluctuations in blood glucose levels in peoplesuffering from diabetes cause long-term, serious complications. Some ofthese complications include blindness, kidney failure, and nerve damage.Additionally, it is known that diabetes is a factor in acceleratingcardiovascular diseases such as atherosclerosis (hardening of thearteries), leading to stroke, coronary heart disease, and otherdiseases. Accordingly, one important and universal strategy in managingdiabetes is to control blood glucose levels.

One way to manage blood glucose levels is testing and monitoring bloodglucose levels by using conventional in vitro techniques, such asdrawing blood samples, applying the blood to a test strip, anddetermining the blood glucose level using colorimetric, electrochemical,or photometric test meters. Another more recent technique for monitoringblood glucose levels is by using an in vivo glucose monitoring system,that continuously or automatically tests glucose, such as for example,the FreeStyle Navigator® Continuous Glucose Monitoring System,manufactured by Abbott Diabetes Care Inc. Unlike conventional bloodglucose meters, continuous analyte monitoring systems employ aninsertable or implantable sensor, which detects and monitors bloodglucose levels. Prior to each use of a new sensor, the userself-implants at least a portion of the sensor under his skin.Typically, an inserter assembly is employed to insert the sensor in thebody of the user. In this manner, an introducer sharp, while engaged tothe sensor, pierces an opening into the skin of the user, releases thesensor and is removed from the body of the user. Accordingly, thereexists a need for an easy-to-use, simple, insertion assembly which isreliable, minimizes pain, and is easy to use.

SUMMARY

Sensor assemblies that include a medical device, such as an analytesensor (e.g., a glucose sensor) and/or an infusion device, and a deviceto position at least a portion of the medical device beneath a skinsurface of a user are provided, as well as methods of positioning atleast a portion of a medical device such as an analyte sensor (e.g., aglucose sensor) and/or an infusion device beneath a skin surface of auser, and methods of analyte testing.

Sensor assembly embodiments include a mount adapted to adhere to a skinof a subject; an analyte sensor coupled to the mount, and an insertionsharp having a longitudinal body including a longitudinal opening toreceive at least a portion of the sensor body.

In certain embodiments, the sensor includes a body having a proximalsection and a distal section, and the distal section may belongitudinally (or otherwise) aligned with the proximal section. Somesensor embodiments may include an intermediate section. An intermediatesection, if present, may be laterally displaced from at least the distalmember (or distal section), and a gap may be defined between thelaterally displaced intermediate section and a portion of the distalsection. In some embodiments, the sensor is integrated with the mount todefine an on-body device such as a single unit on-body device. A secondgap may be defined in the sensor between the proximal section and thelaterally displaced intermediate section. The proximal section of thesensor may have a substantially curved profile.

In some embodiments, the distal section of the sensor body is receivedin the longitudinally defined opening of the insertion sharp. A gap maybe defined between the distal section and the laterally displacedintermediate section, which allows the distal section, in someembodiments a substantial portion—including the entirety of the distalsection, to be received in the longitudinal opening of the insertionneedle. The intermediate section and the proximal section may beproximate the distal section received in the insertion needle.

In some embodiments, the proximal section of the sensor body is incommunication with conductive material disposed on the mount. Theconductive material disposed on the mount may define a printed circuitboard. The proximal section of the sensor may be disposed in ahorizontal plane, and the distal section of the sensor body may bedisposed in a vertical plane. In some embodiments, the sensor is atranscutaneous sensor. In some embodiments, the sensor is configured forimplantation in a soft tissue of a user. In some embodiments, the sensoris a glucose sensor.

Embodiments include sensor assemblies which include a sensor comprisinga portion for operative contact with a fluid of the subject; a mountdefining a distal surface adapted for attachment to the skin of asubject and housing a circuit coupled to sensor for performing afunction with the sensor; and a switch at least partially disposed inthe mount comprising a member having a first position which protrudesfrom the distal surface of the mount and a second position which isrecessed in the mount, the member configured to activate the circuitwhen in the second position.

In some embodiments, the member is biased in the first position. Themember may comprise an elongated member disposed in an opening in themount. In some embodiments, the member is moved from the first positionto the second position when the mount contacts the skin of the subject.In some embodiments, an adhesive layer is disposed on the skin of thesubject, and wherein the member is moved from the first position to thesecond position when the mount contacts the adhesive layer.

In some embodiments, the switch activates the circuit upon the memberreaching the second position. In some embodiments, the switch activatesthe circuit as long as the member is maintained in the second position.In some embodiments, the sensor is a glucose sensor.

In some embodiments, the circuit applies a potential to the sensor. Insome embodiments, the circuit applies a current to the sensor.

In some embodiments, a monitor unit is provided to receive informationfrom the sensor/on-body unit. For example, the system is configured forcommunication (wired or wirelessly) between the on-body unit and amonitor unit, e.g., using radio frequency communication or otherprotocol. The communication between the two units may be active orpassive. In certain embodiments, the on-body unit circuit includescommunication components for wired or wireless transmission of signalrelating to analyte level monitored by the sensor to the monitor unit.In certain embodiments, RFID components may be included in the on-bodyunit and monitor unit to enable RFID communication, in which the on-bodyunit provides data communication to the monitor unit in response to oneor more commands or data communication received from the monitor unit.In some embodiments, the transmitter transmits a signal to the receiverautomatically, e.g., continuously or in certain embodiments onlyperiodically, such as according to a predetermined schedule. In someembodiments, in addition to or instead of automatic data communication,the on-body unit may transmit signal to the receiver only in response toa request for the data, e.g., received from the monitor unit orotherwise initiated by the user (e.g., activation of a switch on thereceiver or on-body unit to initiate data transfer). In someembodiments, a memory is provided, and the circuit stores a signalrelating an analyte level provided by the sensor to the memory. In someembodiments, the sensor is a glucose sensor.

Embodiments include apparatuses for inserting medical devices throughthe skin of a subject. An insertion apparatus may include a sheathdefining a distal surface for placement on the skin of the subject; ahandle movable between a proximal position and distal position relativeto the sheath; a device support for supporting the medical device anddefining an aperture therethrough; a sharp support for supporting asharp extending through said aperture and coupled to the handle; anddriver for biasing the handle and the sharp support towards the proximalposition.

In some embodiments, the driver comprises a compression member such as acompression spring. In some embodiments, the handle is at leastpartially disposed within the sheath. In some embodiments, the handle isat least partially disposed surrounding the sheath. In some embodiments,a bellows portion is provided which is disposed between the handle andthe sheath.

In some embodiments, the sharp support is permanently fixed to thehandle. In some embodiments, the device support is permanently affixedto the handle.

In some embodiments, a stop portion for retaining the device support inthe distal position is included. In some embodiments, the device supportis coupled to the sharp support until the device support reaches adistal position.

In some embodiments, the device support is uncoupled from the sharpsupport when the device support reaches the distal position. In someembodiments, a retention member is provided to couple the sharp supportto the sheath when the sharp support is disposed in the proximalposition.

In some embodiments, the medical device is an analyte sensor. In someembodiments, the medical device is a glucose sensor. In someembodiments, the medical device is an infusion set.

In certain embodiments, apparatuses for inserting a medical devicethrough the skin of a subject, are provided which include a sheathdefining a distal surface for placement on the skin of the subject; ahandle movable between a proximal position and distal position; a devicesupport for supporting the medical device and defining an aperturetherethrough, the device support coupled to the handle; a sharp supportfor supporting a sharp extending through said aperture and coupled tothe device support; and driver for biasing the sharp support towards theproximal position.

In some embodiments, the driver comprises a compression spring. In someembodiments, the handle is at least partially disposed surrounding thesheath.

In some embodiments, a stop portion for retaining the device support inthe distal position is included. In some embodiments, the device supportis coupled to the sharp support until the device support reaches adistal position. In some embodiments, the device support is uncoupledfrom the sharp support when the device support reaches the distalposition.

Embodiments of analyte sensors are provided which include a body havinga proximal section and a distal section. The distal section may belongitudinally aligned with the proximal section. An intermediatesection may be included between the proximal and distal sections, and insome embodiments the intermediate section is laterally displaced from atleast the distal member. A gap may be defined between the laterallydisplaced intermediate section and a portion of the distal section.

In some embodiments, the intermediate section is laterally displacedfrom at least a portion of the proximal section of the sensor body. Asecond gap may be defined between the laterally displaced intermediatesection and the proximal section of the sensor body. The intermediatesection may have a distal end and a proximal end, and further theproximal section may be coupled to the proximal section and the distalsection may be coupled to the distal section of the sensor body. In someembodiments, the intermediate section is a longitudinal member. Theproximal end may be proximate to the gap defined between the distalmember and the intermediate member.

In some embodiments, the proximal end is received within a needle seatto create an anchor region to allow the sensor body to slide into anopening defined in the insertion sharp but prevent the sensor body frominadvertently slipping out of the insertion needle. In some embodiments,a width of the distal section of the sensor body is sized to fit withinthe opening of the insertion sharp having a diameter less than about 22to about 24 gauge.

In some embodiments, the intermediate member includes a plane-alteringportion. The plane-altering portion allows the proximal section of thesensor body to be in a plane different than the distal section of thesensor body. In some embodiments, the proximal section and the distalsection are in planes substantially perpendicular to each other, e.g.,the area may define an angle of about 120° to about 60°, e.g., about 90degrees.

In some embodiments, the proximal section has a curved portion.

In some embodiments, the sensor body includes conductive materialdisposed in or on a surface thereto to define one or more electrodes.The sensor body may include conductive material defining traces disposedin or on a surface of the sensor body. The traces are in communicationwith the one or more electrodes. The traces may be disposed in or on atleast surface of the proximal section of the sensor body. The one ormore electrodes may be disposed on the distal section of the sensorbody. At least one of the traces or electrodes may include a metal orcarbon material such as gold, platinum, titanium, carbon. At least oneof the traces or electrodes may be formed by ablation of material. Theablation may include laser ablation.

In some embodiments, the sensor comprises a sensing layer. The sensinglayer may comprise an enzyme. The sensing layer may comprise an electrontransfer agent. The electron transfer agent may be a redox mediator. Insome embodiments, the electron transfer agent includes osmium transitionmetal complexes and one or more ligands. The electron transfer agent maybe configured to transfer electrons directly between the analyte and theworking electrode. The electron transfer agent may be configured totransfer electrons indirectly between the analyte and the workingelectrode.

In some embodiments, the sensing layer comprises a redox polymer. Theredox polymer may include osmium. The sensing layer may include acatalyst. The catalyst may include an enzyme. The catalyst may act as anelectron transfer agent. In some embodiments, the enzyme includesglucose oxidase. In some embodiments, the enzyme includes glucosedehydrogenase.

In some embodiments, the sensing layer is configured such that thereaction of glucose in the presence of an enzyme forms hydrogenperoxide, and glucose level may be correlated to the level of hydrogenperoxide. In some embodiments, the sensor is a subcutaneous sensor.

These and other features, objects and advantages of the disclosedsubject matter will become apparent to those persons skilled in the artupon reading the detailed description as more fully described below.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of various aspects, features, and embodiments ofthe subject matter described herein is provided with reference to theaccompanying drawings, which are briefly described below. The drawingsare illustrative and are not necessarily drawn to scale, with somecomponents and features being exaggerated for clarity. The drawingsillustrate various aspects and features of the present subject matterand may illustrate one or more embodiment(s) or example(s) of thepresent subject matter in whole or in part.

FIG. 1 is a schematic view of the system in accordance with oneembodiment of the disclosed subject matter;

FIG. 2 is a view, in partial cross section, of an electrochemical sensorin accordance with one embodiment of the disclosed subject matter;

FIG. 3 is a view of an electrochemical sensor in accordance with anotherembodiment of the disclosed subject matter;

FIG. 4 is a view of the electrochemical sensor of FIG. 3 in a foldedconfiguration in accordance with the disclosed subject matter;

FIG. 5 is a view of an electrochemical sensor in accordance with afurther embodiment of the disclosed subject matter;

FIG. 6 is a view of the electrochemical sensor of FIG. 5 in a foldedconfiguration in accordance with the disclosed subject matter;

FIG. 7 is a perspective view of an on-body unit in accordance with oneembodiment of the disclosed subject matter;

FIG. 8 is a perspective view in partial cross-section of an on-body unitof FIG. 7 in accordance with the disclosed subject matter;

FIG. 9 is a schematic view of the system in accordance with oneembodiment of the disclosed subject matter;

FIG. 10 is a sectional, perspective view of another embodiment of aninserter in accordance with the disclosed subject matter;

FIGS. 11-12 are perspective views of components of the inserter of FIG.10 in accordance with the disclosed subject matter;

FIG. 13 is a sectional view of a component of the inserter of FIG. 10 inaccordance with the disclosed subject matter;

FIGS. 14-15 are a perspective views of components of the inserter ofFIG. 10 in accordance with the disclosed subject matter;

FIG. 16 is a sectional view of the component of FIG. 14 in accordancewith the disclosed subject matter;

FIGS. 17-18 are schematic views of a needle hub in accordance with oneembodiment of the disclosed subject matter;

FIG. 19 is a distal end view of a sharp in accordance with oneembodiment of the disclosed subject matter;

FIG. 20 is a side view of a sharp in accordance with one embodiment ofthe disclosed subject matter;

FIG. 21 is a side view of a sharp in accordance with one embodiment ofthe disclosed subject matter;

FIG. 22 is a perspective view with parts of an inserter in accordancewith one embodiment of the disclosed subject matter;

FIG. 23 is a perspective view with parts separated of an inserter inaccordance with one embodiment of the disclosed subject matter;

FIG. 24 is an enlarged sectional view with parts separated of aninserter in accordance with one embodiment of the disclosed subjectmatter;

FIGS. 25-27 are perspective views of components of the inserter of FIG.10 in accordance with the disclosed subject matter;

FIGS. 28-31 are sectional views of the inserter of FIG. 10 in accordancewith the disclosed subject matter;

FIGS. 32-33 illustrate a power supply switch mechanism includingconductive plug of the on-body integrated sensor and sensor electronicsassembly in accordance with embodiments of the disclosed subject matter;

FIGS. 34A-36B illustrate a power supply switch mechanism includingconductive pads on the on-body integrated sensor and sensor electronicsassembly in accordance with embodiments of the disclosed subject matter;

FIG. 37 illustrates a power supply switch mechanism including aninternal switch with a push rod activation of the on-body integratedsensor and sensor electronics assembly in accordance with embodiments ofthe disclosed subject matter;

FIG. 38 illustrates power supply switch mechanism including introducerretraction trigger activation of the on-body integrated sensor andsensor electronics assembly in accordance with embodiments of thedisclosed subject matter;

FIG. 39 illustrates a power supply switch mechanism with a contactswitch of the on-body integrated sensor and sensor electronics assemblyin accordance with embodiments of the disclosed subject matter;

FIGS. 40-41 illustrate a power supply switch mechanism with a batterycontact locking mechanism of the on-body integrated sensor and sensorelectronics assembly in accordance with embodiments of the disclosedsubject matter;

FIGS. 42-43 illustrate a power supply switch mechanism with a bi-modaldome switch of the on-body integrated sensor and sensor electronicsassembly in accordance with embodiments of the disclosed subject matter.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A detailed description of the disclosure is provided herein. It shouldbe understood, in connection with the following description, that thesubject matter is not limited to particular embodiments described, asthe particular embodiments of the subject matter may of course vary. Itis also to be understood that the terminology used herein is for thepurpose of describing particular embodiments only, and is not intendedto be limiting, since the scope of the disclosed subject matter will belimited only by the appended claims.

Where a range of values is provided, it is understood that eachintervening value between the upper and lower limit of that range andany other stated or intervening value in that stated range, isencompassed within the disclosed subject matter. Every range stated isalso intended to specifically disclose each and every “subrange” of thestated range. That is, each and every range smaller than the outsiderange specified by the outside upper and outside lower limits given fora range, whose upper and lower limits are within the range from saidoutside lower limit to said outside upper limit (unless the contextclearly dictates otherwise), is also to be understood as encompassedwithin the disclosed subject matter, subject to any specificallyexcluded range or limit within the stated range. Where a range is statedby specifying one or both of an upper and lower limit, ranges excludingeither or both of those stated limits, or including one or both of them,are also encompassed within the disclosed subject matter, regardless ofwhether or not words such as “from”, “to”, “through”, or “including” areor are not used in describing the range.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosed subject matter belongs. Although anymethods and materials similar or equivalent to those described hereincan also be used in the practice or testing of the present disclosedsubject matter, this disclosure may specifically mention certainexemplary methods and materials.

All publications mentioned in this disclosure are, unless otherwisespecified, incorporated herein by reference for all purposes, includingwithout limitation to disclose and describe the methods and/or materialsin connection with which the publications are cited.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosedsubject matter is not entitled to antedate such publication by virtue ofprior invention. Further, the dates of publication provided may bedifferent from the actual publication dates, which may need to beindependently confirmed.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise.

Nothing contained in the Abstract or the Summary should be understood aslimiting the scope of the disclosure. The Abstract and the Summary areprovided for bibliographic and convenience purposes and due to theirformats and purposes should not be considered comprehensive.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentdisclosed subject matter. Any recited method can be carried out in theorder of events recited, or in any other order which is logicallypossible. Reference to a singular item, includes the possibility thatthere are plural of the same item present. When two or more items (forexample, elements or processes) are referenced by an alternative “or”,this indicates that either could be present separately or anycombination of them could be present together except where the presenceof one necessarily excludes the other or others.

System Overview

Certain classes of analyte monitors are provided in small, lightweight,battery-powered and electronically-controlled systems. Such a system maybe configured to detect signals indicative of in vivo analyte levelsusing an electrochemical sensor, and collect such signals, with orwithout processing the signal. In some embodiments, the portion of thesystem that performs this initial processing may be configured toprovide the raw or initially processed data to another unit for furthercollection and/or processing. Such provision of data may be effected,for example, via a wired connection, such as an electrical, or via awireless connection, such as an IR or RF connection.

Certain analyte monitoring systems for in vivo measurement employ asensor that measures analyte levels in interstitial fluids under thesurface of the subject's skin. These may be inserted partially throughthe skin (“transcutaneous”) or entirely under the skin (“subcutaneous”).A sensor in such a system may operate as an electrochemical cell. Such asensor may use any of a variety of electrode configurations, such as athree-electrode configuration (e.g., with “working”, “reference” and“counter” electrodes), driven by a controlled potential (potentiostat)analog circuit, a two-electrode system configuration (e.g., with onlyworking and counter electrodes), which may be self-biasing and/orself-powered, and/or other configurations. In some embodiments, thesensor may be positioned within a blood vessel.

In certain systems, the analyte sensor is in communication with a sensorcontrol unit. As used in this disclosure, an on-body unit sometimesrefers to such a combination of an analyte sensor with such a sensorcontrol unit.

Certain embodiments are modular. The on-body unit may be separatelyprovided as a physically distinct assembly, and configured to providethe analyte levels detected by the sensor over a communication link to amonitor unit, referred to in this disclosure as a “receiver unit” or“receiver device”, or in some contexts, depending on the usage, as a“display unit,” “handheld unit,” or “meter”. The monitor unit, in someembodiments, may include, e.g., a mobile telephone device, a personaldigital assistant, other consumer electronic device such as MP3 device,camera, radio, etc., or other communication-enabled data processingdevice.

The monitor unit may perform data processing and/or analysis, etc. onthe received analyte data to generate information pertaining to themonitored analyte levels. The monitor unit may incorporate a displayscreen, which can be used, for example, to display measured analytelevels, and/or audio component such as a speaker to audibly provideinformation to a user, and/or a vibration device to provide tactilefeedback to a user. It is also useful for a user of an analyte monitorto be able to see trend indications (including the magnitude anddirection of any ongoing trend), and such data may be displayed as well,either numerically, or by a visual indicator, such as an arrow that mayvary in visual attributes, such as size, shape, color, animation, ordirection. The receiver device may further incorporate an in vitroanalyte test strip port and related electronics in order to be able tomake discrete (e.g., blood glucose) measurements.

The modularity of these systems may vary. In some embodiments the sensoris attachable and detachable from the sensor control unit (and theon-body unit may be reusable), while in other embodiments, the sensorand sensor control unit may be provided as an integrated, un-detachablepackage, which may be disposable after use.

FIG. 1 shows one embodiment of an analyte measurement system 10. In sucha system, a data processing unit or sensor control unit 12 may interactwith an analyte sensor 14 to obtain signals representative of analytelevels. Sensor control unit 12 may further include communicationscircuit with associated electronics (not shown). In some embodiments,the sensor control unit 12 and sensor are constructed to be maintained“on the body” of the subject for a period of time that may includehours, days, weeks, or a month or more. Accordingly, the sensor controlunit 12 and sensor 14 may be referred to collectively herein as anon-body unit 16. A receiver unit or monitor unit 18 may also beprovided. In the embodiment shown, sensor control unit 12 and monitorunit 18 communicate via connection 20 (in this embodiment, a wireless RFconnection). Communication may occur, e.g., via RF communication,infrared communication, Bluetooth® communication, Zigbee® communication,802.1x communication, or WiFi communication, etc. In some embodiments,the communication may include an RF frequency of 433 MHz, 13.56 MHz, orthe like. In some embodiments, a secondary monitor unit 22 may beprovided. A data processing terminal 24 is useful for providing furtherprocessing or review of analyte data.

In certain embodiments, system 10 may be a continuous analyte monitor(e.g., a continuous glucose monitoring system or CGM), and accordinglyoperate in a mode in which the communications via connection 20 hassufficient range to support a flow of data from on-body unit 16 tomonitor unit 18. In some embodiments, the data flow in a CGM system isautomatically provided by the on-body unit 16 to the monitor unit 18.For example, no user intervention may be required for the on-body unit16 to send the data to the monitor unit 18. In some embodiments, theon-body unit 16 provides the signal relating to analyte level to thereceiving unit 18 on a periodic basis. For example, the signal may beprovided, e.g., automatically sent, on a fixed schedule, e.g., onceevery 250 ms, once a second, once a minute, etc. In some embodiments,the signal is provided to the monitor unit 18 upon the occurrence of anevent, e.g., a hyperglycemic event or a hypoglycemic event, etc. In someembodiments, data processing unit 12 may further include local memory inwhich it may record, “logged data” or buffered data collected over aperiod of time and provide the some or all of the accumulated data tomonitor unit 18 from time-to-time. Or, a separate data logging unit maybe provided to acquire periodically transmitted data from a transmitterdevice. Data transmission in a CGM system may be one-way communication,e.g., the on-body unit 16 provides data to the monitor unit 18 withoutreceiving signals from the monitor unit 18. In some embodiments, two-waycommunication is provided between the on-body unit 16 and the monitorunit 18.

In some embodiments, a signal is provided to the monitor unit 18 “ondemand.” According to such embodiments, the monitor unit 18 requests asignal from the on-body unit 16, or the on-body unit 16 may be activatedto send signal upon activation to do so. Accordingly, one or both of theon-body unit 16 and monitor unit 18 may include a switch activatable bya user or activated upon some other action or event, the activation ofwhich causes analyte-related signal to be transferred from the on-bodyunit 16 to the monitor unit 18. For example, the monitor unit 18 isplaced in close proximity with a transmitter device and initiates a datatransfer, either over a wired connection, or wirelessly by variousmeans, including, for example various RF-carried encodings and protocolsand IR links.

In some embodiments, the signal relating to analyte level isinstantaneously generated by the analyte sensor 14 upon receipt of therequest, and transmitted to the monitor unit 18 as requested, and/or thesignal relating to analyte level is periodically obtained, e.g., onceevery 250 ms, once a second, once a minute, etc. Upon receipt of the “ondemand” request at the on-body unit 16, an analyte signal is provided tothe monitor unit. In some cases, the signal provided to the monitor unit18 is or at least includes the most recent analyte signal(s).

In further embodiments, additional data is provided to the monitor unit18 “on demand.” For example, analyte trend data may be provided. Suchtrend data may include two or more analyte data points to indicate thatanalyte levels are rising, falling, or stable. Analyte trend data mayinclude data from longer periods of time, such as, e.g., severalminutes, several hours, several days, or several weeks.

Further details regarding on demand systems are disclosed in U.S. Pat.No. 7,620,438, U.S. Patent Publication Nos. 2009/0054749 A1, publishedFeb. 26, 2009; 2007/0149873 A1, published Jun. 28, 2007, now U.S. Pat.No. 9,014,773; 2008/0064937 A1, published Mar. 13, 2008; 2008/0071157A1, published Mar. 20, 2008; 2008/0071158 A1, published Mar. 20, 2008;2009/0281406 A1, published Nov. 12, 2009; 2008/0058625 A1, publishedMar. 6, 2008, now U.S. Pat. No. 7,920,907; 2009/0294277 A1, publishedDec. 3, 2009; 2008/0319295 A1, published Dec. 25, 2008, now U.S. Pat.No. 8,597,188; 2008/0319296 A1, published Dec. 25, 2008, now U.S. Pat.No. 8,617,069; 2009/0257911 A1, published Oct. 15, 2009, now U.S. Pat.No. 8,252,229; 2008/0179187 A1, published Jul. 31, 2008, now U.S. Pat.No. 8,808,515; 2007/0149875 A1, published Jun. 28, 2007, now U.S. Pat.No. 8,515,518; 2009/0018425 A1, published Jan. 15, 2009, now U.S. Pat.No. 8,160,670; and U.S. patent application Ser. No. 12/625,524, filedNov. 24, 2009, now U.S. Pat. No. 8,390,455; Ser. No. 12/625,525, filedNov. 24, 2009, now U.S. Pat. No. 8,358,210; Ser. No. 12/625,528, filedNov. 24, 2009, now U.S. Pat. No. 8,115,635; Ser. No. 12/628,201, filedNov. 30, 2009, now U.S. Patent Publication No. 2010/0076280; Ser. No.12/628,177, filed Nov. 30, 2009, now U.S. Patent Publication No.2010/0076289; Ser. No. 12/628,198, filed Nov. 30, 2009, now U.S. PatentPublication No. 2010/0076291; Ser. No. 12/628,203, filed Nov. 30, 2009,now U.S. Patent Publication No. 2010/0076292; Ser. No. 12/628,210, filedNov. 30, 2009, now U.S. Patent Publication No. 2010/0076293; Ser. No.12/393,921, filed Feb. 26, 2009, now U.S. Patent Publication No.2010/0213057; 61/149,639, filed Feb. 3, 2009; Ser. No. 12/495,709, filedJun. 30, 2009, now U.S. Patent Publication No. 2010/0326842; 61/155,889,filed Feb. 26, 2009; 61/155,891, filed Feb. 26, 2009; 61/155,893, filedFeb. 26, 2009; 61/165,499, filed Mar. 31, 2009; 61/227,967, filed Jul.23, 2009; 61/163,006, filed Mar. 23, 2009; 12/495,730, filed Jun. 30,2009, now U.S. Patent Publication No. 2010/0331643; Ser. No. 12/495,712,filed Jun. 30, 2009, now U.S. Pat. No. 8,437,827; 61/238,461, filed Aug.31, 2009; 61/256,925, filed Oct. 30, 2009; 61/238,494, filed Aug. 31,2009; 61/238,159, filed Aug. 29, 2009; 61/238,483, filed Aug. 31, 2009;61/238,581, filed Aug. 31, 2009; 61/247,508, filed Sep. 30, 2009;61/247,516, filed Sep. 30, 2009; 61/247,514, filed Sep. 30, 2009;61/247,519, filed Sep. 30, 2009; 61/249,535, filed Oct. 7, 2009; Ser.No. 12/544,061, filed Aug. 19, 2009, now U.S. Patent Publication No.2011/0046466; Ser. No. 12/625,185, filed Nov. 24, 2009, now U.S. Pat.No. 8,354,013; Ser. No. 12/625,208, filed Nov. 24, 2009, now U.S. Pat.No. 9,042,954; Ser. No. 12/624,767, filed Nov. 24, 2009, now U.S. PatentPublication No. 2011/0124993; Ser. No. 12/242,780, filed Sep. 30, 2008,now U.S. Pat. No. 8,983,568; Ser. No. 12/183,602, filed Jul. 31, 2008,now U.S. Patent Publication No. 2010/0030052; Ser. No. 12/211,014, filedSep. 15, 2008, now U.S. Pat. No. 8,636,884; and Ser. No. 12/114,359,filed May 2, 2008, now U.S. Pat. No. 8,080,385, each of which isincorporated by reference in its entirety herein.

The Sensor

The analyte sensor 14 of the analyte measurement system 10 may be usedto monitor levels of a wide variety of analytes. Analytes that may bemonitored include, for example, acetyl choline, amylase, bilirubin,cholesterol, chorionic gonadotropin, creatine kinase (e.g., CK-MB),creatine, DNA, fructosamine, glucose, glutamine, growth hormones,hormones, ketones, lactate, peroxide, prostate-specific antigen,prothrombin, RNA, thyroid stimulating hormone, and troponin. Theconcentration of drugs, such as, for example, antibiotics (e.g.,gentamicin, vancomycin, and the like), digitoxin, digoxin, drugs ofabuse, theophylline, and warfarin, may also be monitored. One or moreanalyte may be monitored by a given sensor.

In one embodiment of the present disclosure, sensor 14 is physicallypositioned in or on the body of a user whose analyte level is beingmonitored. Sensor 14 may be configured to continuously sample theanalyte level of the user and convert the sampled analyte level, e.g.,glucose concentration into a corresponding data signal, e.g., a currentor voltage, for input into sensor control unit electronics.Alternatively, sensor 14 may be configured to sample analyte levels ondemand. The sensor control unit electronics may amplify, filter, orotherwise process the signal provided by the sensor.

The sensor may take on a number of forms. For example, the sensor mayinclude a flexible or rigid substrate. In some embodiments, the sensormay be a wire. In some embodiments, the sensor may include two or threeor more electrodes.

An embodiment of the sensor 14 is illustrated in FIG. 2. In someembodiments, sensor 14 includes a substrate which is a dielectric, e.g.,a polymer or plastic material, such as polyester or polyamide. In thisembodiment, the sensor is constructed so that a portion is positionablebeneath skin and a portion is above skin. Accordingly, sensor 14includes an insertion portion 30 and a contact portion 32. The contactportion 32 typically includes several conductive contacts 36, 38, and 40(herein shown as 3 contacts) for connection to other electronics, e.g.,at the data processing unit 12. The contacts provided in this embodimentare for a working electrode 36, a reference electrode 38, and a counterelectrode 40. In some embodiments, two or more working electrodes areprovided. The operative portions of these electrodes, that is, workingelectrode, reference electrode, and counter electrode (not individuallyshown), are provided at the distal end of insertion portion 30. Thecontact and operative portions of the electrodes are connected bycircuit traces 42, 44, and 46 running on the surface of substrate. Insome embodiments, the traces are provided in channels, or may beembedded within the substrate, or may traverse different sides of thesubstrate. The conductive contacts, conductive traces, and electrodesare fabricated from a conductive material, such as platinum, palladium,gold, or conductive carbon. Further details of sensors are described,e.g., in U.S. Pat. Nos. 6,175,572; 6,103,033, which are incorporated byreference herein.

Sensor 14 may include a proximal retention portion 48. In someembodiments, the insertion portion 30 and the proximal retention portion48 are substantially longitudinally aligned. The insertion portion 30and the proximal retention portion 48 are sized and configured to bepositioned with a sharp for installation into the skin of a subject, asdescribed herein. In use, the sensor 14 may be configured to bend (e.g.,along the line B) and therefore be positioned in two substantiallyperpendicular, intersecting planes.

As illustrated in FIG. 3, sensor 14′ is substantially identical tosensor 14, with many of the differences illustrated in FIG. 3 and notedherein. Sensor 14′ further includes additional features useful forconnecting to, e.g., mounting to or in or on, a housing associated withthe sensor control unit 12. For example, sensor 14′ includes a laterallydisplaced portion (or sensor tab) 50′ and a longitudinal displacedportion 52′ which provide a path for electrical connections, e.g., theconductive traces. Sensor 14′ is further provided with a notch 54′between the proximal retention portion 48′ and the longitudinaldisplaced portion 52′. Such configuration permits the sensor 14′ to bend(e.g., along the line are indicated by line B) and therefore bepositioned in two substantially perpendicular, intersecting planes, asillustrated in FIG. 4. As will be described below, the sensor tab 50′can be encased in a portion of the body of the data processing unit 12to aid in securing and positioning the sensor 14′. Proximal retentionportion 48′ maintains its longitudinal alignment with insertion portion30′ for positioning within an insertion sharp.

FIG. 5 illustrates a further embodiment of a sensor 14″ in accordancewith the disclosure. Sensor 14″ is substantially identical to sensor 14and 14′, with certain exemplary differences illustrated in FIG. 5 andnoted herein. For example, sensor 14″ includes a contact portion 32″which defines a fan-like configuration having a curved edge. Sensor 14″defines a sensor flag indentation 56″ which also serves to assist inretaining the sensor 14″ in vertical direction, as will be describedbelow, and provides a discrete location for mating with a feature of thedata processing unit 12, e.g., the bottom surface of a printed circuitboard. Sensor 14″ is likewise capable of bending along axis B, asillustrated in FIG. 6. In any of the embodiments of the sensor describedherein, the distance between insertion portion 30 to retention portion48 may be, e.g., about 5 mm, or about 10 mm, or about 15 mm, or about 20mm.

In general, sensors in accordance with the present disclosure operateelectrochemically, through an arrangement of electrodes having chemicalsensing layers applied thereto, by generating an electrical currentproportional to the volume of a redox reaction of the analyte (andindicative of analyte concentration), catalyzed by an analyte-specificoxidizing enzyme. Embodiments exist in which the number of electrodesprovided to bring about and detect the level of these reactions is two,three or a greater number.

A portion of sensor 14 (which collectively refers to sensors 14′ and 14″herein) may be situated above the surface of the skin, with a distalportion 30 penetrating through the skin and into the subcutaneous spacein contact with the user's biofluid, such as interstitial fluid. Thedisposition of the sensor in the illustrated embodiment is referred toas “transcutaneous”. In general, the term “transcutaneous” as usedherein refers to a sensor that is only partially inserted under one ormore layers of the skin of the user, whereas the term “subcutaneous”refers to a sensor that is completely inserted under one or more layersof the skin of the user. It is understood that many features describedherein would be applicable to both transcutaneous and subcutaneoussensors. Further details regarding the electrochemistry of sensor 14 isprovided in U.S. Pat. Nos. 5,264,104; 5,356,786; 5,262,035, 5,320,725,6,990,366, each of which is incorporated herein by reference

In some embodiments, the sensor is implantable into a subject's body fora period of time (e.g., three to seven days, or in some embodiments,longer periods of up to several weeks) to contact and monitor an analytepresent in a biological fluid. In this regard, the sensor can bedisposed in a subject at a variety of sites (e.g., abdomen, upper arm,thigh, etc.), including intramuscularly, transcutaneously,intravascularly, or in a body cavity. In one embodiment, the sensor canbe a transcutaneous glucose sensor. Alternatively, the sensor can be asubcutaneous glucose sensor.

In some embodiments, sensor 14 is employed by insertion and/orimplantation into a user's body for some usage period. In suchembodiments, substrate may be formed from a relatively flexible materialto improve comfort for the user and reduce damage to the surroundingtissue of the insertion site, e.g., by reducing relative movement of thesensor with respect to the surrounding tissue.

While the embodiments illustrated in FIGS. 2-6 have three electrodes,other embodiments can include a fewer or greater number of electrodes.For example, a two electrode sensor can be utilized. The sensor may beexternally-powered and allow a current to pass proportional to theamount of analyte present. Alternatively, the sensor itself may act as acurrent source in some embodiments. In some two-electrode embodiments,the sensor may be self-biasing and there may be no need for a referenceelectrode. An exemplary self-powered, two-electrode sensor is describedin U.S. patent application Ser. No. 12/393,921, filed Feb. 26, 2009, andentitled “Self-Powered Analyte Sensor,” which is hereby incorporated byreference in its entirety herein for all purposes. The level of currentprovided by a self-powered sensor may be low, for example, on the orderof nanoamperes.

On-Body Unit

An exemplary configuration for sensor 14 (and sensors 14′ and 14″) andsensor control unit 12 (e.g., collectively on-body unit 16) isillustrated in FIGS. 7-8. Data processing unit 12, may be provided witha substantially circular configuration having a reduced height (i.e.,“Z”-dimension) to provide a low-profile when sitting on the skin of thesubject. In some embodiments, the height is about 3 mm to about 25 mm,e.g., may be about 4 mm, about 5 mm, about 10 mm, or about 15 mm. Incertain embodiments, the unit 12 may have a variable height. Dataprocessing unit 12, including its associated electronics 80, are housedin a sensor housing 122. For example, electronics may include, e.g., ananalog interface for connecting to the sensor 14, a processor, and apower supply. A serial communication section may be provided. Atemperature sensor, such as a thermistor, which detects skin and orambient temperature may be included to provide compensation to theanalyte signal. A RF communication circuit is provided to communicatewith the monitor unit 18. A data storage unit may be provided to storeanalyte data points over a short term, e.g., several hours or minutes,or over a long term, e.g., several days or weeks. Additional optionalelectronics include a serial communication section, a leakage detectioncircuit, or user input, e.g., a switch to activate/deactivate some orall of the device. Many of the components may be combined togetherand/or their function provided by common components. Furthermore,certain components may be eliminated entirely. For example, a powersupply may be omitted if power is provided by inductive coupling.

In some embodiments, sensor 14 is disposed within the data transmittingunit 12, e.g., in a bent configuration, as illustrated in certainembodiments herein, e.g., in FIGS. 4 and 6. The contact portion 32 ofsensor 14 may be oriented in a substantially horizontal configuration,and secured to a printed circuit board of the transmitter unit 12. Theinsertion portion 30 of the sensor 14 extends in a substantiallydownwardly vertical orientation for placement in the skin of thesubject. It is understood that sensor 14 may be disposed in otherconfigurations, e.g., in an entirely substantially verticalconfiguration, etc. As a further example, the insertion portion 30 maybe disposed at an oblique angle, e.g., between about 0° and about 90°with respect to the skin surface.

As illustrated in FIG. 9, the on-body unit 16 communicates with themonitor unit 18. Such communication may be one-way communication, e.g.,from the on-body unit 16 to the monitor unit 18. In some embodiments,the communication may be two-way, e.g., both from the on-body unit 16 tothe receiving unit 18 and from the receiving unit 18 to the on-body unit16. In such cases, the receiving unit 18 may also be referred to hereinas a display unit, transceiver or handheld unit. Communication betweenthe on-body unit 16 and monitor unit 18 may occur via RF communication,inductive coupling, direct wired connection, etc.

Insertion Assembly

An insertion assembly is provided, which is used to install a medicaldevice to the subject. In some embodiments, the insertion assemblyincludes an inserter and the medical device itself. The inserter can beconfigured to insert various medical devices to the subject, such as forexample, an analyte sensor, an infusion set, a cannula, or a lancet. Insome embodiments, the inserter can be configured to install acombination of such devices, e.g., a combined sensor/infusion set, etc.In certain embodiments, a given inserter can be configured to install afirst device and a second device at different times. For example, aninserter may be modifiable to be used with more than one medical device,include more than one type of medical device, e.g., by attaching anadapter and/or removing detaching a portion of an inserter. The insertercan install the medical device transcutaneously in, under, or throughthe skin of the subject; or subcutaneously; or placed on the surface ofthe skin. The medical device can include features or structures, e.g.,barbs, tabs, adhesive, etc., to maintain the device in position withrespect to the skin after insertion.

In other embodiments, the insertion assembly includes an inserter, amedical device, such as an analyte sensor, and a mount for supportingthe medical device at least partially in or on the skin of the subject.The mount may be inserted simultaneously with the medical device by theinserter. In other embodiments, the mount is installed after or beforeinstallation of the medical device. In such case the mount may beapplied by the inserter or separately. The mount may include features orstructures to maintain the sensor in position with respect to the skinafter insertion.

In further embodiments, the insertion assembly includes an inserter, ananalyte sensor, a mount, and a power supply. The mount and power supplymay be inserted simultaneously with the analyte sensor by the inserter.In other embodiments, the mount and battery are installed after orbefore installation of the analyte sensor. In such case the mount and/orpower supply may be applied by the inserter or separately.

In still further embodiments, the insertion assembly includes aninserter, a medical device such as an analyte sensor, a mount, andelectronics. The mount and electronics may be inserted simultaneouslywith the analyte sensor by the inserter. In other embodiments, the mountand electronics are installed after or before installation of theanalyte sensor. For example, the mount and the analyte sensor may beinstalled by the inserter, and the electronics may be subsequentlyinstalled. In other embodiments, the mount is installed, followed byinsertion of the analyte sensor by the inserter, and further followed byinstallation of the electronics. In other embodiments, the mount andelectronics are installed first, and the analyte sensor is subsequentlyinstalled.

In some embodiments, the electronics provide a voltage or current to theanalyte sensor. In some embodiments, the electronics processes signalsprovided by the analyte sensor. In further embodiments, the electronicsmay include communication functionality for providing a signal relatingto the signal provided by the analyte sensor to a further component,such as, e.g., a monitor unit, a handheld unit, a meter, a display unit,a computer, or other component. In some embodiments, communicationscircuitry, such as RFID antenna or communications circuitry is provided.

The inserter can include a plurality of different components. Forexample, the inserter may include one or more components for advancing asharp towards the skin of the subject. The sensor and associatedelectronics and/or mounting structure may be supported by a supportstructure, such as a carriage. An actuator may be provided for advancingthe sharp and/or the analyte sensor/support structure. In someembodiments, the actuator is coupled to the sharp and/or supportstructure, such that manual force and speed applied by the user to theactuator is transferred to the sharp and/or support structure.

The inserter can also include one or more components for retracting thesharp, while allowing the analyte sensor and optional mount and/orelectronics to remain to the subject. The components for retracting thesharp can include a retractor. It is understood that the retractor andthe actuator may be the same structure or include some commoncomponents. In some embodiments, the retractor is directly or indirectlycoupled to the sharp such that the manual force applied by the user istransferred from the retractor to the sharp to retract the sharp fromthe skin. In other embodiments, a drive assembly may be provided toretract the sharp. For example, the drive assembly may include a spring,motor, hydraulic piston, etc., to retract the sharp away from the skinof the subject. The drive assembly may also include a linear drivecomponent.

In some embodiments, the retractor withdraws the sharp upon actuation bythe user. In such cases, the user actuates the retractor when it isdesired to withdraw the sharp. For example, the retractor may include arelease switch. Upon activation of the release switch, the driveassembly, e.g., the spring or other driver, retracts the sharp from theskin. In other embodiments, the retractor and the actuator comprisecommon components. After activating the actuator to advance the sharpand the analyte sensor, the user releases the actuator, which allows thedrive assembly to withdraw the sharp from the skin.

In some embodiments, the retractor withdraws the sharp without furtheruser interaction after actuation of insertion. For example, the insertermay include features or components which automatically retract the sharpupon advancement of the sharp and support structure by a predeterminedamount. Inserter devices, in which no further action by the user isrequired to initiate withdrawal of the sharp after insertion, arereferred to herein as having “automatic” withdrawal of the sharp.

Inserter Devices

An inserter 100 in accordance with an exemplary embodiment isillustrated in FIG. 10. Inserter 100 includes a handle 102 and aremovable distal cap 104. The cap 104 may maintain a sterile,contaminant-free environment for the medical device and sharp housedtherein. As illustrated in FIGS. 10-16, distal cap 104 is secured tohandle 102, e.g., by use of one or more mating members, e.g., threads110 and 111, or hooks, tape, and the like. Inserter 100 includes a base142 which defines a distal, substantially planar surface 112 forplacement on the skin S of a subject, and in other embodiments may be acurved or inclined surface, e.g., a concave or convex surface. Inserter100 may be utilized to advance a medical device into the skin of thesubject, e.g., an analyte sensor, and infusion set, etc. In someembodiments, handle 102 is advanced relative to base 142 in order toadvance the medical device into the skin of the patient, as will bedescribed in greater detail herein.

The components of inserter 100 are illustrated in FIGS. 11-27. Asillustrated in FIG. 11, handle 102 includes a contact surface 114 forcontact by a user to insert and install the sensor housing 122 andsensor 14. Threads 110 are provided on handle 102 for attachment to cap104 via threads 111 (as illustrated in FIGS. 12-13). Cap 104 can includean upwardly extending boss 125 to assist positioning of the sharp 124.The distal portion of cap 104 includes a recess 115 for retaining adesiccant 190 therein. In some embodiments, a silica gel or molecularsieves may be used. Such material can be in either in granular form(pellets) or pressed into tablets. In some embodiments, silica geltablets are used.

Cap 104 is provided with one or more apertures 117, which allows forpassage of air to the desiccant 190 to remove moisture from the interiorof the inserter 100. Cap 104 includes an annular ridge 113 which engagesthe distal edge portion 116 of handle 102. In some embodiments, annularridge 113 prevents distal movement of handle 102 (as well as sharp 124)when cap 104 is attached to handle 102.

Base 142, as illustrated in FIGS. 10 and 14, includes a distal sheathportion 192, which shields sharp 124 prior to deployment and a distalrim 112 having a substantially planar surface configuration to rest onthe subject's skin. Base 142 also includes side walls 191, which alongwith inner rail 128 defines a recess for retraction spring 146. Base 142provides a spring floor 148, as illustrated in FIG. 29.

Support member or shuttle 134, as illustrated in FIGS. 15-16, supportsneedle hub 136, from which sharp 124 extends longitudinally within theinserter 100. In some embodiments, the sharp is supported at an obliqueangle, e.g., between about 0° and about 90° with respect to the skinsurface. Needle hub 136 can be secured to shuttle 134 via aninterlocking O-ring configuration, adhesive, or other techniques knownin the art. In some embodiments, sharp 124 is a solid needle. In someembodiments, sharp 124 is provided with a substantially cylindricalconfiguration defining an interior bore, e.g., a rigid cannula or ahypodermic-style needle.

Needle hub 136 is further illustrated in FIGS. 17-18. Needle hub 136supports sharp 124, having a sharpened distal portion 160. In someembodiments, as discussed herein, a longitudinal wall opening or gap 162is provided in at least a portion of the wall of the sharp 124. Thelength N of the gap 162 is selected to be commensurate with the lengthof the insertion portion 30 through to the proximal retention portion 48of the sensor, or about 5 mm, or about 10 mm, or about 15 mm, or about20 mm. The length L of the sharp 124 may be about 5 mm, or about 10 mm,or about 20 mm, about 30 mm, or about 50 mm, and is selected based uponthe desired depth of the insertion portion 30 of the sensor 14.

The distal portion 160 of sharp 124 is illustrated in greater detail inFIGS. 19-21. As illustrated in FIG. 19, sharp 124 has a substantially“C”- or “U”-shaped profile in this embodiment, but may have otherconfigurations, e.g., substantially “V”-shaped. A longitudinal gap 162is provided in the wall of the sharp 124. FIG. 20 illustrates distalportion 160 is provided with an angled tip. In some embodiments, theangled tip may be provided with a first angled tip portion 164 and asecond steep-angled tip portion 166. The exemplary configuration, whichincludes multiple edges and faces, provides a sharp point to reducepenetration force, trauma, and bleeding for the subject. The distalsection of the sensor body has a width sized to fit within the notch 162of the insertion sharp 124 having a diameter less than about 22 to about24 gauge, in certain embodiments the sharp is 25 gauge. In someembodiments, sharp 124 is a fabricated from a sheet of metal, and foldedinto a substantially “V” or “U” or “C” configuration in cross-section.In some embodiments, a laser is used to form the wall opening or gap162.

FIGS. 22-23 illustrate the position of sensor housing 122 with respectto the needle hub 136 and sharp 124. As illustrated in FIG. 22, thesharp 124 extends through an aperture 168 in the sensor housing 122. Thedistal portion of sensor 14 is positioned with the sharp 124. As furtherillustrated in FIG. 23, electronics 80 (e.g., a printed circuit boardcontaining ASIC electronics) and sensor hub 123 are positioned withinsensor housing 122. A power supply 82, such as a battery, e.g., a singleuse disposable battery, or rechargeable battery, is provided. In someembodiments, the active operational life of the battery may exceed theactive operational life of the sensor 14.

FIG. 24 illustrates in cross-section the orientation of the sensorhousing 122 with respect to the sharp 124 of inserter 100. As discussedherein, sensor 14 is disposed in a substantially bent configuration,such that a portion of the sensor, e.g., the insertion portion 30 andthe proximal retention portion 48 are substantially vertical (e.g.,substantially aligned with the longitudinal axis of the inserter 100 andsubstantially perpendicular to the skin surface) and the contact portion32 (shown in profile) is oriented in a substantially horizontalconfiguration, and in electrical contact with the data processing unitelectronics, such as circuit 80. The sensor tab 50 can be encased in theplastic of the sensor housing 122 (e.g., “overmolded”) and secured inplace. The notch 56 provides further stability to the sensor 14, e.g.,by allowing the sensor tab 50 to be encased by the material of thesensor housing 122, and further provides a means for verticallyorienting the sensor 14 during mounting, e.g., by allowing verticalpositioning of the notch 56 with respect to a vertical landmark of thehousing 122.

The sensor 14, mounted with the sensor housing 122, is disposed withinthe concave recess in the carriage 130. In the initial configuration ofthe inserter 100 (see, e.g., FIGS. 10 and 28-29) the sharp 124 extendsthrough a longitudinal aperture 168 formed in a carriage 130. In someembodiments, the aperture 168 is appropriately sized, such that neitherthe sharp 124 nor needle hub 136 is in contact with the carriage 130.Accordingly, the needle hub 136 (and sharp 124) on the one hand, and thecarriage 130 and the sensor housing 122, on the other hand, movesimultaneously but independently from one another. In other embodiments,a friction fit may be provided between the aperture and the sharp.

The insertion portion 30 and proximal retention portion 48 of the sensor14 are disposed within a longitudinal bore 162 within the sharp 124.(See, e.g., FIG. 19) The proximal retention portion 48 is disposedwithin the longitudinal bore of the sharp and provides additionalstability to the mounting of the sensor 14 within the sharp 124. Thelongitudinal wall gap or opening 162 of sharp 124 is aligned with thesensor 14, such that the tab 50 and the contact portion 32 extendlaterally outward from the sharp 124.

With continued reference to FIGS. 15 and 16, shuttle 134 includes wings182 and resilient distally-extending fingers 184. Inner rail 128 isillustrated in FIG. 25. As illustrated in FIG. 26, shuttle 134 is sizedand configured for slidable movement within inner rail 128. Wings 182 ofshuttle 134 are configured for slidable movement within axial notches188 of inner rail 128. When fingers 184 of shuttle 134 are disposed intheir normally biased outward position, fingers 184 engage the lowersurface 194 of inner rail 128. In the configuration illustrated in FIG.26, shuttle 134 is locked with respect to inner rail 128. As will bediscussed herein, fingers 184 may be biased radially inward to allowupward movement of shuttle 134 relative to inner rail 128.

As illustrated in FIG. 10, inner rail includes an upper surface 186 forengagement with handle 102. In some embodiments, surface 186 is adheredor otherwise fixed to handle 102.

The relationship of inner rail 128, shuttle 134 and base 142 isillustrated in FIG. 27. In an initial configuration, inner rail 128 andshuttle 134 are in a locked relationship by engagement of wings 182 andfingers 184. Inner rail 128 and shuttle 134 are axially movable withinbase 142. Spring 146, which is secured between spring floor 148 of base142 and wings 182 of shuttle 134 biases the inner rail 128 and shuttle134 in a proximal (upward) direction.

Inserter 100 is illustrated in section in FIGS. 28-29 prior to use in asensor pre-deployment position. Cap 104 is attached to the distalportion of inserter 100, via inter-engagement of threads 110 and 111.

As illustrated in FIG. 28, the inserter 100 includes an initialconfiguration in which the handle 102 is disposed in a proximal positionwith respect to the base 142. In such configuration, the sharp 124 isdisposed in a configuration spaced apart from an aperture of theadhesive layer 118.

As illustrated in FIG. 30, inner rail 128 includes a carriage 130. In asensor insertion position, the handle 102 is depressed downward (arrowD) against the bias of spring 146, the inner rail 128 moves downwardlywith the carriage 130 and the sensor housing 122. Shuttle 134 supportsneedle hub 136, from which sharp 124 extends longitudinally within theinserter 100. Initially shuttle 134 is coupled to inner rail 128 viainter-engagement of fingers 184 of shuttle 134 with distal surface 194of inner rail 128, and both shuttle 134 and inner rail 128 move distallytogether as a unit.

As the sharp 124 is urged distally (FIG. 30), it carries the sensorinsertion portion 30 of sensor 14 into the subcutaneous portion of thesubject's skin S and into contact with the interstitial fluid. Ascarriage 130 reaches a distal position, the distal surface of the sensorhousing 122 engages the upper surface of adhesive pad 118, therebybecoming adhered to the skin surface S of the subject.

Flanges 170 on base 142 engage fingers 184 of shuttle 134. Fingers 184are pivoted or bend inwards by contact with flanges 170 (as indicated byarrows F).

As illustrated in FIG. 31, such pivoting of fingers 184 causes fingers184 to become disengaged from distal edge 194 of inner rail 128. Shuttle134 is thereby disengaged from inner rail 128. Disengagement of theshuttle 134 from the inner rail 128 permits the spring 146 to expand,thereby advancing the shuttle 134 to a proximal position, andwithdrawing the sharp 124 from the sensor 14 and the skin S of thesubject, while leaving the sensor 14 in the skin. Once the sharp hasbeen withdrawn from the subject, it is no longer accessible from thedistal portion of the inserter 100, which prevents accidental needlesticks. When the carriage 130 reaches the distal position in whichflanges 170 engage fingers 184 of needle shuttle 134, needle shuttle 134withdraws needle 124 automatically without further input from the user.

Prior to activation of the integrated sensor 14 and sensor electronicsassembly 16 for use, there may be a period of time from themanufacturing that the assembly 16 may be in a “sleep” or “idle” mode.With a power supply such as a battery integrated within the assembly,for reasons including cost optimization and prolonging shelf life,embodiments of the present disclosure include systems that are activatedmerely by positioning the sensor 14 and electronics unit 16 on a skinsurface as described above, i.e., no additional action may be requiredof the user other than applying a force to housing 122. As such,insertion of the sensor 14 and/or mounting of the housing 122 causesactivation of the electronics 80. In certain embodiments, activationswitch configurations are included which may be configured to betriggered, for example, by the insertion device activation, therebyturning on the integrated sensor and sensor electronics assembly into anactive mode.

As illustrated in FIG. 29, inserter 100 is also provided with a plungerswitch 185, which provides automatic activation of the electronics 80 ofthe data processing unit 12. In some embodiments, the plunger switch 185is a longitudinally slidable member disposed on the distal surface ofthe sensor housing 122. When the sensor housing is advanced proximally,it engages the adhesive pad 118, or alternatively the skin surface ofthe subject. Upon such engagement, the plunger switch 185 is movedaxially (proximally) with respect to the housing 122. The plunger switchin the proximal position is shown in FIG. 30, for example. Such axialmovement is used to activate the sensor electronics 80. In someembodiments, the plunger switch is spring biased. Accordingly, as longas the sensor housing is maintained in a fixed relationship with theadhesive pad 118 against the bias, electronic activation is maintained.If the sensor housing is removed from the adhesive or the skin, theplunger switch moves with the bias, and the electronics are deactivated.In other embodiments, the plunger switch provides a one-time activationof the electronics. In such cases, once the electronics are activated,the sensor housing is not required to remain in contact with theadhesive or the skin in order to maintain activation.

As illustrated in FIGS. 32-33, embodiments of a power supply switchmechanism include conductive plugs of the on-body integrated sensor andsensor electronics assembly 16 in accordance with the presentdisclosure. FIGS. 32-33 illustrate enlarged sectional views of sensorhousing 122. As shown, the sensor electronics assembly circuit board 710may be provided with a physical gap 750 that breaks the electricalcircuit between the power supply (e.g., battery) and the other circuitryof the sensor electronics assembly.

In one embodiment, when the predetermined force is applied on theinsertion device 100 as discussed above, a conductive portion 720provided within the housing 122 of the sensor electronics may be movedin a direction as shown by arrow 730 such that electrical contact isestablished in the physical gap 750 on the circuit board, by forexample, the conductive portion 720 coming into physical contact withthe conductive portions 760 of the circuit board 710. In this manner, inone embodiment, the electrical path from the power supply and theremaining circuitry on the circuit board of the sensor electronics iscompleted, thereby powering the sensor electronics.

By way of another example, referring to FIG. 33, the conductive portions760 of the circuit board are provided on the board itself, and theconductive plug 740, for example, when pushed into the cavity 750,establishes electrical contact between the conductive portions 760 ofthe circuit board.

In one embodiment, as discussed above, the actuation of the insertiondevice 100 to position the sensor and sensor electronics assemblytriggers the switch mechanism shown in FIGS. 32-33 by also moving theconductive portion 720 or the conductive plug 760 in the directioncomplimentary to the direction of the introducer movement, and therebyswitching on the sensor electronics. Within the scope of the presentdisclosure, the activation of the sensor electronics by moving theconductive portion 720 or the conductive plug may include a separateprocedure, where after positioning the sensor and the sensor electronicsassembly on the skin surface, a predetermined force is applied on thehousing of the integrated sensor 14 and sensor electronics assembly suchthat the desired movement of the conductive portion 720 or theconductive plug 760 may be achieved.

FIGS. 34A-36B illustrate another configuration of the power supplyswitch mechanism including conductive pads of the on-body integratedsensor and sensor electronics assembly in accordance with embodiments ofthe present disclosure. Referring to FIG. 34A, an exposed conductivering 771 may be provided and configured to contact the surface of thecircuit board in the sensor housing 122 (shown in cross section in FIG.34B) such that, the insertion device activation positions the conductivering 771 on the surface of the circuit board so as to complete theelectrical contact of the sensor housing 122 (by for example, manualforce applied on the insertion device placing the conductive ring incontact with the circuit board of the sensor electronics).

Referring to FIGS. 35A-B, in another aspect, electrical contact pads772, 773 may be provided to the circuit board in the sensor housing 122(shown in cross section in FIG. 35B, such that the mating of the contactpads with the conductive ring 771 switches on the sensor electronicsdevice to provide power to the device from its power source. FIGS. 36A-Bshow yet another configuration of the switch activation mechanism inaccordance with the present disclosure, where a portion of theconductive ring 774 is selectively positioned and provided to establishelectrical contact in the sensor housing 122 (shown in cross section inFIG. 36B).

As discussed, each of the activation configurations described aboveincludes a break in the circuitry from the power source such that thepower supply is not drained when the device is not in use, and uponactivation, the break in the electrical contact is completed, therebypowering the device and activating it for operation.

FIG. 37 illustrates a power supply switch mechanism including aninternal switch with a push rod activation of the on-body integratedsensor and sensor housing 122 in accordance with embodiments of thepresent disclosure. As shown, in one embodiment, push rod 810 may beprovided and positioned in the sensor electronics such that when a forceis applied in the direction as shown by arrow 830, the push rod 810 isdisplaced in the same direction and completes the electrical contactbetween the two contacts 820, 821. In one aspect, the push rod 810 maybe provided within a seal 840 such as an O-ring or similar components.

FIG. 38 illustrates power supply switch mechanism including introducerretraction trigger activation of the on-body integrated sensor andsensor housing 122 in accordance with embodiments of the presentdisclosure. As shown, a nonconducting needle or device 910 is providedto physically separate two electrical contacts 920, 921. Each of theelectrical contacts 920, 921 is biased or spring loaded to be urgedtowards each other, physically separated by the nonconducting needle910. Accordingly, when the nonconducting needle 910 is retracted orpulled away from the sensor electronics assembly in the direction asshown by arrow 930, the electrical contacts 920, 921 are configured tocontact each other, thereby completing the break in the circuit andestablishing electrical connection to activate the sensor electronicsassembly. In one aspect, the nonconducting device or needle 910 mayinclude, for example, but not limited to, glass, plastic or any othermaterial suitable to separate two electrical contacts and provideinsulation therebetween.

FIG. 39 illustrates power supply switch mechanism with a contact switchof the on-body integrated sensor and sensor electronics assembly inaccordance with embodiments of the present disclosure. As shown, in afurther aspect, there is provided an electronic switch 1001 (that isconfigured to draw an insubstantial amount of power from the sensorelectronics power supply), and when triggered, completes the breakbetween the contacts 1010, 1011 by physically contacting the twocontacts 1010, 1011 with the activation component 1002 that completesthe circuit in the sensor electronics from its power supply such asbattery to activate the device for operation.

FIGS. 40-41 illustrate a power supply switch mechanism with a batterycontact locking mechanism of the on-body integrated sensor and sensorelectronics assembly 122 in accordance with the present disclosure.Referring to FIGS. 40-41, in still another aspect, the battery contactof the sensor electronics may be provided with a barbed tab 1110. Inpost manufacturing shelf mode when the device is nonoperational, the tab1110 is positioned within the sensor electronics housing in the positionas shown in FIG. 40 so that it is not in contact with the conductivecontact 1120 of the sensor electronics circuit board. When in use asshown in FIG. 41, the tab 1110 may be biased such that it physicallycontacts the conductive contact 1120 on the circuit board, therebyclosing the circuit to/from the battery/power source and thus activatingor switching on the sensor electronics. As shown in the Figures, the tab1110 may be configured that upon biasing to establish contact with theconductive contact 1120, it locks or latches with the conductive contact1120 and the circuit board so as to maintain the electrical connection.

FIGS. 42-43 illustrate power supply switch mechanism with a bi-modaldome switch of the on-body integrated sensor and sensor electronicsassembly in accordance with embodiments of the present disclosure. Yetin another embodiment, a bi-modal dome shaped switch 1210 is provided onthe circuit board of the sensor electronics assembly such that, whenpressed down (as shown in FIG. 42), the dome shaped layer 1210 (whichmay include, for example, a thin sheet metal dome) may be configured toretain the concave shape as shown in FIG. 43 and effectively closing thecircuit on the circuit board at the contact point 1220. In one aspect,the dome shaped layer 1210 may be configured to shunt to short two ormore electrical contacts at the contact point 1220 of the circuit board.Alternatively, the dome shaped layer 1210 may be connected to thecircuit board such that one end of the dome shaped layer 1210 is incontact with one of the two or more open electrical contacts, and thedepression of the dome shaped layer 1210 closes the circuit on thecircuit board by physically contacting the other one or more of the openelectrical contacts.

In the manner described above, in accordance with various embodiments ofthe present disclosure, sensor electronics activation switchconfigurations are provided that may be triggered or activatedautomatically or semi-automatically in response to the activation of theinsertion device described above, or alternatively, may be separatelyactivated by the user by, for example, depressing upon a portion of thehousing or switch provided on the housing of the sensor electronics.Accordingly, power consumption may be optimized for the sensorelectronics assembly while improving post manufacturing shelf life ofthe device prior to use or activation.

It is understood that the subject matter described herein is not limitedto particular embodiments described, as such may, of course, vary. It isalso understood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present subject matter is limited onlyby the appended claims.

Additional detailed description of embodiments of the disclosed subjectmatter are provided in but not limited to: U.S. Pat. Nos. 7,299,082;7,167,818; 7,041,468; 6,942,518; 6,893,545; 6,881,551; 6,773,671;6,764,581; 6,749,740; 6,746,582; 6,736,957; 6,730,200; 6,676,816;6,618,934; 6,616,819; 6,600,997; 6,592,745; 6,591,125; 6,560,471;6,540,891; 6,514,718; 6,514,460; 6,503,381; 6,461,496; 6,377,894;6,338,790; 6,299,757; 6,299,757; 6,284,478; 6,270,455; 6,175,752;6,161,095; 6,144,837; 6,143,164; 6,121,009; 6,120,676; 6,071,391;5,918,603; 5,899,855; 5,822,715; 5,820,551; 5,628,890; 5,601,435;5,593,852; 5,509,410; 5,320,715; 5,264,014; 5,262,305; 5,262,035;4,711,245; 4,545,382; U.S. Patent Publication No. 2004/0186365,published Sep. 23, 2004, now U.S. Pat. No. 7,811,231; U.S. PatentApplication No. 61/238,646, filed Aug. 31, 2009, the disclosures of eachof which is incorporated herein by reference.

1-20. (canceled)
 21. An insertion assembly, comprising: (a) an on-bodyunit, comprising: a housing comprising a top surface and a bottomsurface, wherein the top surface comprises an opening of the topsurface, wherein the bottom surface comprises an opening of the bottomsurface, and wherein a longitudinal axis extends through the opening ofthe top surface and the opening of the bottom surface; a glucose sensorcomprising at least two electrodes; and sensor electronics disposedwithin the housing and coupled with the glucose sensor; and (b) aninserter, comprising: a proximal end, a distal end, and an interior; anda sharp, wherein the on-body unit and the sharp are entirely disposed inthe interior of the inserter, wherein at least a portion of the glucosesensor is disposed in the sharp, wherein the inserter is configured toadvance the on-body unit and the sharp from a first position to a secondposition such that the sharp pierces skin of a user and the housing ofthe on-body unit is secured to the skin of the user in the secondposition, wherein the sharp extends through the opening of the topsurface and the opening of the bottom surface along the longitudinalaxis when the on-body unit is in the first position, wherein the distalend of the inserter is configured to be positioned on the skin of theuser before advancement of the on-body unit and the sharp, wherein theinserter is further configured to automatically retract the sharp fromwithin the user and entirely into the interior of the inserter and leavea part of the glucose sensor in the skin of the user, and wherein thedistal end of the inserter is further configured to be removed from theskin of the user after automatic retraction of the sharp from within theuser.
 22. The insertion assembly of claim 21, further comprising anadhesive portion configured to secure the housing to the skin of theuser, wherein the adhesive portion is further configured to extendoutwardly beyond the bottom surface of the housing along the skin in alldirections when the housing is secured to the skin of the user.
 23. Theinsertion assembly of claim 22, wherein the adhesive portion is disposedon the bottom surface of the housing before advancement of the on-bodyunit and sharp.
 24. The insertion assembly of claim 21, wherein adistance between the housing when the on-body unit is in the firstposition and the housing when the on-body unit is in the second positionis greater than a maximum height of the housing.
 25. The insertionassembly of claim 21, wherein the sensor electronics comprise aprocessor, a power source, an analog interface, a data storage unit, andwireless communication circuitry configured to communicate dataindicative of a glucose level.
 26. The insertion assembly of claim 21,wherein the sharp is configured to pierce the skin of the user at anangle substantially perpendicular to the skin of the user.
 27. Theinsertion assembly of claim 21, wherein the on-body unit and the sharpare configured to advance in a linear direction when advancing from thefirst position to the second position.
 28. The insertion assembly ofclaim 21, wherein the on-body unit further comprises a side wall of thehousing, wherein the side wall is located between the top surface andthe bottom surface, wherein the side wall comprises a first portion anda second portion, and wherein the second portion of the side walldefines a non-orthogonal angle relative to both the first portion of theside wall and the top surface of the housing.
 29. The insertion assemblyof claim 21, wherein the sensor electronics are in a sleep mode or anidle mode when the on-body unit is in the first position.
 30. Theinsertion assembly of claim 21, wherein the sensor electronics areconfigured to be activated when the on-body unit is at or near thesecond position.
 31. The insertion assembly of claim 21, wherein thesensor electronics further comprise an opening of the sensor electronicsalong the longitudinal axis, and wherein the sharp extends through theopening of the sensor electronics when the on-body unit is in the firstposition.
 32. The insertion assembly of claim 21, wherein the proximalend of the inserter comprises an inserter handle, wherein the distal endof the inserter comprises an inserter base, wherein the inserter handleis configured to move in a downward direction toward the skin of theuser relative to the inserter base in response to an application offorce on the inserter handle, and wherein the inserter is configured toadvance the on-body unit and the sharp from the first position to thesecond position after the application of force on the inserter handle.33. The insertion assembly of claim 21, further comprising a capremovably attached to a distal portion of the inserter by a plurality ofthreads, wherein the cap comprises an interior space comprising asterile environment, and wherein the cap further comprises a pluralityof vertically extending grooves spaced apart around an outer perimetersurface of the cap.
 34. The insertion assembly of claim 21, wherein aheight profile of the housing is less than or equal to approximately 10millimeters.
 35. The insertion assembly of claim 21, further comprisinga sensor hub, wherein the glucose sensor comprises a distal sensorportion and a proximal sensor portion, wherein the distal sensor portionis configured to sense a glucose level of the user, wherein the proximalsensor portion is engaged with the sensor hub, and wherein the distalsensor portion is substantially orthogonal to the proximal sensorportion.
 36. The insertion assembly of claim 21, wherein the distal endof the inserter defines a plane, and wherein the bottom surface of thehousing is parallel to the plane when the on-body unit is in the firstposition.
 37. The insertion assembly of claim 21, wherein the opening ofthe top surface is a first opening of the top surface, wherein the topsurface further comprises a second opening of the top surface, whereinthe first opening of the top surface has a first maximum width, andwherein the second opening of the top surface has a second maximum widthless than the first maximum width.
 38. The insertion assembly of claim21, wherein the on-body unit is configured to be disposed after a singleuse.
 39. An insertion assembly, comprising: (a) an on-body unit,comprising: a housing comprising a top surface and a bottom surface,wherein the top surface comprises an opening of the top surface, whereinthe bottom surface comprises an opening of the bottom surface, andwherein a longitudinal axis extends through the opening of the topsurface and the opening of the bottom surface; a glucose sensorcomprising at least two electrodes; and sensor electronics disposedwithin the housing and coupled with the glucose sensor, wherein thesensor electronics comprise a processor, a power source, an analoginterface, a data storage unit, and wireless communication circuitryconfigured to communicate data indicative of a glucose level; and (b) aninserter, comprising: a proximal end, a distal end, and an interior; anda sharp; wherein the on-body unit and the sharp are entirely disposed inthe interior of the inserter, wherein at least a portion of the glucosesensor is disposed in the sharp, wherein the inserter is configured toadvance the on-body unit and the sharp in a linear direction from afirst position to a second position such that the sharp pierces skin ofa user and the housing of the on-body unit is secured to the skin of theuser in the second position, wherein a distance between the housing whenthe on-body unit is in the first position and the housing when theon-body unit is in the second position is greater than a maximum heightof the housing, wherein a height profile of the housing is less than orequal to approximately 10 millimeters, wherein the sharp extends throughthe first opening of the top surface and the opening of the bottomsurface along the longitudinal axis when the on-body unit is in thefirst position, wherein the distal end of the inserter is configured tobe positioned on the skin of the user before advancement of the on-bodyunit and the sharp, wherein the inserter is further configured toautomatically retract the sharp from within the user and entirely intothe interior of the inserter and leave a part of the glucose sensor inthe skin of the user, wherein the inserter further comprises a driverfor retracting the sharp from within the user, wherein the drivercomprises a spring, and wherein the distal end of the inserter isfurther configured to be removed from the skin of the user afterautomatic retraction of the sharp from within the user.
 40. Theinsertion assembly of claim 39, wherein the sharp is configured topierce the skin of the user at an angle substantially perpendicular tothe skin of the user.
 41. The insertion assembly of claim 40, whereinthe sensor electronics further comprise an opening of the sensorelectronics along the longitudinal axis, and wherein the sharp extendsthrough the opening of the sensor electronics when the on-body unit isin the first position.
 42. The insertion assembly of claim 41, furthercomprising an adhesive portion configured to secure the housing to theskin of the user, wherein the adhesive portion is configured to extendoutwardly beyond the bottom surface of the housing along the skin in alldirections when the housing is secured to the skin of the user.
 43. Theinsertion assembly of claim 42, wherein the distal end of the inserterdefines a plane, and wherein the bottom surface of the housing isparallel to the plane when the on-body unit is in the first position.44. The insertion assembly of claim 42, wherein the proximal end of theinserter comprises an inserter handle, wherein the distal end of theinserter comprises an inserter base, wherein the inserter handle isconfigured to move in a downward direction toward the skin of the userrelative to the inserter base in response to an application of force onthe inserter handle, and wherein the inserter is configured to advancethe on-body unit and the sharp from the first position to the secondposition after the application of force on the inserter handle.
 45. Theinsertion assembly of claim 42, wherein the sensor electronics are in asleep mode or an idle mode when the on-body unit is in the firstposition.
 46. The insertion assembly of claim 42, wherein the sensorelectronics are configured to be activated when the on-body unit is ator near the second position.
 47. The insertion assembly of claim 42,wherein the on-body unit further comprises a side wall of the housing,wherein the side wall is located between the top surface and the bottomsurface, wherein the side wall comprises a first portion and a secondportion, and wherein the second portion of the side wall defines anon-orthogonal angle relative to both the first portion of the side walland the top surface of the housing.
 48. The insertion assembly of claim42, further comprising a sensor hub, wherein the glucose sensorcomprises a distal sensor portion and a proximal sensor portion, whereinthe distal sensor portion is configured to sense a glucose level of theuser, wherein the proximal sensor portion is engaged with the sensorhub, and wherein the distal sensor portion is substantially orthogonalto the proximal sensor portion.
 49. The insertion assembly of claim 42,further comprising a cap removably attached to a distal portion of theinserter by a plurality of threads, wherein the cap comprises aninterior space comprising a sterile environment, and wherein the capfurther comprises a plurality of vertically extending grooves spacedapart around an outer perimeter surface of the cap.
 50. The insertionassembly of claim 42, wherein the opening of the top surface is a firstopening of the top surface, wherein the top surface further comprises asecond opening of the top surface, wherein the first opening of the topsurface has a first maximum width, and wherein the second opening of thetop surface has a second maximum width less than the first maximumwidth.